A comprehensive analysis of 27,704 Iranian adults found that only one-third received complete lifestyle counseling from healthcare providers, while 11% received no recommendations at all. The study documented significant disparities, with females, rural residents, and patients with multiple conditions more likely to receive guidance on diet, exercise, weight management, and smoking cessation. When counseling was delivered, meaningful behavioral changes followed: adults receiving physical activity advice showed 21% higher odds of meeting exercise guidelines, while smokers given cessation counseling were 83% more likely to attempt quitting. A clear dose-response relationship emerged for nutrition counseling, with those receiving six versus two or fewer dietary recommendations showing 32% better diet quality. This represents one of the largest assessments of preventive care delivery patterns globally, providing crucial insights into how healthcare systems can better leverage provider-patient interactions for disease prevention. The findings suggest that while provider counseling effectively influences behavior when delivered, systemic gaps in consistent delivery may represent a missed opportunity for population health improvement. However, as a preprint awaiting peer review, these results require validation before informing policy changes in healthcare delivery systems.